﻿/* Blob.js
 * A Blob implementation.
 * 2013-06-20
 * 
 * By Eli Grey, http://eligrey.com
 * By Devin Samarin, https://github.com/eboyjr
 * License: X11/MIT
 *   See LICENSE.md
 */

/*global self, unescape */
/*jslint bitwise: true, regexp: true, confusion: true, es5: true, vars: true, white: true,
  plusplus: true */

/*! @source http://purl.eligrey.com/github/Blob.js/blob/master/Blob.js */

if (true || typeof Blob !== "function" || typeof URL === "undefined")
    if (false && typeof Blob === "function" && typeof webkitURL !== "undefined") var URL = webkitURL;
    else var Blob = (function (view) {
        "use strict";

        var BlobBuilder = view.BlobBuilder || view.WebKitBlobBuilder || view.MozBlobBuilder || view.MSBlobBuilder || (function (view) {
            var
                  get_class = function (object) {
                      return Object.prototype.toString.call(object).match(/^\[object\s(.*)\]$/)[1];
                  }
                , FakeBlobBuilder = function BlobBuilder() {
                    this.data = [];
                }
                , FakeBlob = function Blob(data, type, encoding) {
                    this.data = data;
                    this.size = data.length;
                    this.type = type;
                    this.encoding = encoding;
                }
                , FBB_proto = FakeBlobBuilder.prototype
                , FB_proto = FakeBlob.prototype
                , FileReaderSync = view.FileReaderSync
                , FileException = function (type) {
                    this.code = this[this.name = type];
                }
                , file_ex_codes = (
                      "NOT_FOUND_ERR SECURITY_ERR ABORT_ERR NOT_READABLE_ERR ENCODING_ERR "
                    + "NO_MODIFICATION_ALLOWED_ERR INVALID_STATE_ERR SYNTAX_ERR"
                ).split(" ")
                , file_ex_code = file_ex_codes.length
                , real_URL = view.URL || view.webkitURL || view
                , real_create_object_URL = real_URL.createObjectURL
                , real_revoke_object_URL = real_URL.revokeObjectURL
                , URL = real_URL
                , btoa = view.btoa
                , atob = view.atob
                , can_apply_typed_arrays = false
                , can_apply_typed_arrays_test = function (pass) {
                    can_apply_typed_arrays = !pass;
                }

                , ArrayBuffer = view.ArrayBuffer
                , Uint8Array = view.Uint8Array
            ;
            FakeBlob.fake = FB_proto.fake = true;
            while (file_ex_code--) {
                FileException.prototype[file_ex_codes[file_ex_code]] = file_ex_code + 1;
            }
            try {
                if (Uint8Array) {
                    can_apply_typed_arrays_test.apply(0, new Uint8Array(1));
                }
            } catch (ex) { }
            if (!real_URL.createObjectURL) {
                URL = view.URL = {};
            }
            URL.createObjectURL = function (blob) {
                var
                      type = blob.type
                    , data_URI_header
                ;
                if (type === null) {
                    type = "application/octet-stream";
                }
                if (blob instanceof FakeBlob) {
                    data_URI_header = "data:" + type;
                    if (blob.encoding === "base64") {
                        return data_URI_header + ";base64," + blob.data;
                    } else if (blob.encoding === "URI") {
                        return data_URI_header + "," + decodeURIComponent(blob.data);
                    } if (btoa) {
                        return data_URI_header + ";base64," + btoa(blob.data);
                    } else {
                        return data_URI_header + "," + encodeURIComponent(blob.data);
                    }
                } else if (real_create_object_URL) {
                    return real_create_object_URL.call(real_URL, blob);
                }
            };
            URL.revokeObjectURL = function (object_URL) {
                if (object_URL.substring(0, 5) !== "data:" && real_revoke_object_URL) {
                    real_revoke_object_URL.call(real_URL, object_URL);
                }
            };
            FBB_proto.append = function (data/*, endings*/) {
                var bb = this.data;
                // decode data to a binary string
                if (Uint8Array && (data instanceof ArrayBuffer || data instanceof Uint8Array)) {
                    if (can_apply_typed_arrays) {
                        bb.push(String.fromCharCode.apply(String, new Uint8Array(data)));
                    } else {
                        var
                              str = ""
                            , buf = new Uint8Array(data)
                            , i = 0
                            , buf_len = buf.length
                        ;
                        for (; i < buf_len; i++) {
                            str += String.fromCharCode(buf[i]);
                        }
                    }
                } else if (get_class(data) === "Blob" || get_class(data) === "File") {
                    if (FileReaderSync) {
                        var fr = new FileReaderSync;
                        bb.push(fr.readAsBinaryString(data));
                    } else {
                        // async FileReader won't work as BlobBuilder is sync
                        throw new FileException("NOT_READABLE_ERR");
                    }
                } else if (data instanceof FakeBlob) {
                    if (data.encoding === "base64" && atob) {
                        bb.push(atob(data.data));
                    } else if (data.encoding === "URI") {
                        bb.push(decodeURIComponent(data.data));
                    } else if (data.encoding === "raw") {
                        bb.push(data.data);
                    }
                } else {
                    if (typeof data !== "string") {
                        data += ""; // convert unsupported types to strings
                    }
                    // decode UTF-16 to binary string
                    bb.push(unescape(encodeURIComponent(data)));
                }
            };
            FBB_proto.getBlob = function (type) {
                if (!arguments.length) {
                    type = null;
                }
                return new FakeBlob(this.data.join(""), type, "raw");
            };
            FBB_proto.toString = function () {
                return "[object BlobBuilder]";
            };
            FB_proto.slice = function (start, end, type) {
                var args = arguments.length;
                if (args < 3) {
                    type = null;
                }
                return new FakeBlob(
                      this.data.slice(start, args > 1 ? end : this.data.length)
                    , type
                    , this.encoding
                );
            };
            FB_proto.toString = function () {
                return "[object Blob]";
            };
            return FakeBlobBuilder;
        }(view));

        return function Blob(blobParts, options) {
            var type = options ? (options.type || "") : "";
            var builder = new BlobBuilder();
            if (blobParts) {
                for (var i = 0, len = blobParts.length; i < len; i++) {
                    builder.append(blobParts[i]);
                }
            }
            return builder.getBlob(type);
        };
    }(self));